Kaelen stows his bow, drawing his shortsword and dagger as the Zombies close in. He lashes out at Zombie A with his shortsword, followed by an attack on Zombie B with his off hand dagger

Shortsword: to hit 25, damage 10 + 5 sneak attack.

Dagger: to hit 6, damage 4

Kaelen goes to behead the zombie, and as his shortsword cuts through its neck, it seems to slow for a second, before slicing through the neck. It's dead.

Dagger misses.

Bert/Malachite, you're up.

Feeling a bit more confident as the zombies start to fall, Malachite lifts his hand trying to do the conjuring trick again. A large shadowy mass, shaped vaguely like a large hammer, forms in his hand, and he move over to try to knock one of zombies away from Kaelen, interposing himself.

Bonus Action: Conjure Pact Weapon (Warhammer)
Move: 5ft South, 5ft Southwest
Action: Attack Zombie C: To Hit: 10. Deals 6 bludgeoning damage. Weapon mastery: Push (Push large or smaller enemies up to 10ft): Push Zombie C 5 ft Northwest
Move: 5ft Northwest so he's next to both the zombies.

That hits.

Bert, you're up.

Bert runs zombie E through with his rapier, 14 to hit and 9 damage. Followed by an offhand slash from his dagger to zombie F, 11 to hit and 3 damage

As you run the spear through the zombie, although it seems to have pierced its heart, it does not fall.

Zombies E and F attack Bert in retaliation.

To Hit: 16; Damage: 2

To Hit: 15; Damage: 3

Koya Balrin, you're up.

Bert falls, death save failed.

Koya is going to use their action surge to fire on Zombie D and E with their light crossbow. They will also move to just in front of where Kuhkay is on the map.

First attack on Zombie D: 17+3 to hit.

Damage on Zombie D: 3 damage. Weapon mastery: Slow (speed is reduced by 10 ft until my next turn).

Second attack on Zombie E: 22 to hit. 

Damage on Zombie E: 9 damage. Weapon mastery: Slow

Zombie D is dead, so I'll redirect onto Zombie F.

Both hit.

Although your crossbow bolt pierces through Zombie D's eye, it just keeps stumbling towards you, quite persistently.

Herbert, you're up.

Herbert looks at the chaos and freezes in place. Definitely not moving anywhere. Seeing falling enemies and friends is quite shocking for a pure soul like Herb. He just looks at the ground/gravel road, chooses a jagged rock and casts catapult, to fling it towards zombie Cs head.

DEX 13 save or 17 bludgeoning damage.

As the rock's head makes contact with Zombie C, landing square in its forehead, its head bursts into a fountain of flesh and bone. It's dead.

Zombies A and B turn their hauntingly empty eye sockets onto Malachite.

To Hit: 11

To Hit: 8

Squall, you're up!

Updated map?

Updated in the link.

Squall moves to Zombie E and attacks him with his fists.

24 to hit, 9 Damage.

He then turns to Zombie F and strikes him as well with an unarmed strike.

16 to hit, 9 damage

Both blows connect squarely on the zombies.

Both blows land on the zombies, and although you could've sworn you crushed Zombie E's skull, it keeps up its endless walk, even missing half its head.

Kaelen, you're up.

Kaelen aims a sneak attack at Zombie B with his shortsword.

To hit: 15, Damage: 9 + 6 Sneak Attack with vex

However, his follow up attack with his off-hand dagger misses despite the opening he created.

To hit: 5

The zombies seem quite percistant. Even dealing such a devastatingly strong blow doesn't seem to bring the zombie to its knees.

Malachite, you're up.

Malachite turns the hammer back into a trident and attacks the zombie Kaelen is focusing on, shield raised against it.

Bonus Action: Conjure Pact Weapon (Trident)
Action: Attack Zombie B: To Hit: 8. Deals 10 piercing damage. Weapon mastery: Topple (DC 14 Con Save or Fall Prone).

While the trident hit, for some reason the zombie just won't die. (Didn't Topple)

Zombies E and F, after having taken their fill of Bert's corpse, lurch their way over to Squall.

To Hit: 7

To Hit: 12

Koya, you're up.